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Different types of Steering Systems & Examples

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DIFFERENT TYPES OF STEERING SYSTEM DIFFERENT TYPES OF STEERING SYSTEM

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Steering systems/mechanisms in use

STEERING

RACK & PINION WORM & ROLLER

RACK & PINION

MANUAL

RECIRCULATING BALL & NUT

DRIVEN EPS

HYDROSTATIC PINIONDRIVEN EPS

RACK

COLUMNDRIVEN EPS

RECIRCULATINGBALL & NUT ( GEROTOR )

POWER

HYDRAULIC ELECTRICAL /

RACK & PINION WORM & ROLLER

ELECTRO-HYD

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DIFFERENT TYPES OF STEERING SYSTEM DIFFERENT TYPES OF STEERING SYSTEM

Steering systems/mechanisms in use

Hydraulic Electro-hyd Electric

1 SCREW & NUT X X

2 CAM & LEVER X X

3 WORM & ROLLER X X X

4 RECIRCULATING BALL SCREW & NUT ? ?

5 RACK & PINION

6 GEROTOR X X

MANUALSTEERING MECHANISMS IN USE SL. NO POWER-ASSISSTED

STEERING SYSTEM STEERING RATIO

CONSTANT VARIABLE

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MANUAL STEERING SYSTEMS

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Typical Mechanical Steering Systems( for “on-road vehicles )

Steering Systems

Cars / UVs

UVs/LCVs

Trucks / Bus

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POWER-ASSISSTED STEERING SYSTEMS

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Need forNeed for Power SteeringPower Steering

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NEED FOR POWER STEERING NEED FOR POWER STEERING

The need to achieve the greatest possible road safety under :

INCREASING TRAFFIC DENSITYINCREASING TRAFFIC DENSITYNEXT

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9

NEED FOR POWER STEERING NEED FOR POWER STEERING

The need to achieve the greatest possible road safety under :

HIGH AXLE LOADSHIGH AXLE LOADSNEXT

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NEED FOR POWER STEERING NEED FOR POWER STEERING

POOR ROAD CONDITIONSPOOR ROAD CONDITIONS

PREV

The need to achieve the greatest possible road safety under :

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NEED FOR POWER STEERING NEED FOR POWER STEERING

All of the above situations force the driver to operate the vehicle at slow speeds ,increasing steering effort causing FATIGUE TO DRIVERS.

Judgment of a fatigued driver will be poor.

Poor judgment in driving means increasedpotential for accidents.

LED TO THE DEVELOPMENT LED TO THE DEVELOPMENT OF POWER STEERINGOF POWER STEERINGNEXT

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Benefits ofBenefits of Power SteeringPower Steering

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BENEFITS OF POWER STEERING BENEFITS OF POWER STEERING

EFFORTLESS STEERINGEFFORTLESS STEERING

15 mkg

3 mkg2 mkg

1 mkg

HCV CAR HCV CAR

STEE

RIN

G E

FFO

RTS

AT

PAR

KIN

G

MANUALSTEERING

POWERSTEERING

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BENEFITS OF POWER STEERING BENEFITS OF POWER STEERING

PRECISE & QUICK RESPONSEPRECISE & QUICK RESPONSE

LOCK TO LOCK MANUAL STEERINGTOTAL TURNS 6 TO 7

LOCK TO LOCK POWER STEERING

40

30

20

10

7 6 5 4 3 2 1 0 1 2 3 4 5 6 7

LH TURN RH TURN

TOTAL TURNS 3 TO 4

OU

TPU

T AN

GLE

(DEG

)

INPUT TURNS

SAP

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BENEFITS OF POWER STEERING BENEFITS OF POWER STEERING

ABSORBS ROAD SHOCKSABSORBS ROAD SHOCKS

Vehicle fitted with Manual Steering

Vehicle fitted with Power Steering

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BENEFITS OF POWER STEERING BENEFITS OF POWER STEERING

GREATER SAFETY AND GREATER SAFETY AND CONTROLLABILITY UNDER CRITICAL SITUATIONSCONTROLLABILITY UNDER CRITICAL SITUATIONS

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HYDRAULIC POWER STEERING SYSTEMS

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SYSTEM LAYOUT OF A TYPICAL POWER STEERINGSYSTEM LAYOUT OF A TYPICAL POWER STEERING

Power Steering Pump Power Steering

FI Gear

Power Steering Reservoir

Suction Line

Pressure

Line

ReturnLine

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Steering Systems

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Typical Box-type Power Steering System for CVs ( Tie rod behind the axle )

Reservoir

Power Steering Pump

Integral Power Steering Gear

Pitman Arm

Steering Column

Intermediate Shaft

Tie Rod Tube

Tie Rod End

Draglink

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Integral (Box type) Power Steering SystemSRK

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Typical Cylinder-type Power Steering System for CVs ( Tie rod behind the axle )

(Manual)

Cylinder type Power Steering System

Steering Systems

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21

Typical Box-type Power Steering System for UVs ( Tie rod behind the axle )

Integral (Box type) Power Steering System

Steering Systems

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Cylinder type Power Steering System

Non-typical Cylinder-type Power Steering System for UVs( Tie rod behind the axle )

(Manual)

Steering Systems

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Typical R&P Power Steering System for Cars( Tie rod ahead of the axle )

Rack &Pinion Steering Gear

Steering Wheel

Steering Column

Intermediate ShaftTie Rods

Steering Lever

Steering Systems

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Typical R&P type Power Steering System for Cars / UVs

Integral Rack & Pinion type Power Steering System

Steering Systems

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HYROSTATIC STEERING SYSTEMS

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Typical Hydrostatic Steering System (for “off-road vehicles”)

Steering Systems

Farm Tractors / Earthmovers

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Need for Electro-Hydraulic / Electric Power Steering Systems

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•Fuel efficiency.

•Emission control @ engine idle.

•Control flexibility thro’ S/W change instead of H/W change.

•Integration with other electronic controls on vehiclee.g., ABS, TCS, ESP, etc.

Need for EHPS / EPS

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HPSbelt-driven-pump EPHS

two-speed EPHSmultispeed EPS

100%

25%

15%

10%0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%En

ergy

Con

sum

ptio

n

Energy Consumption of Different Power Steering Systems

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Electro-Hydraulic Power Steering Systems(EHPS)

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Motor-Pump-UnitSteering Gear

Feed & ReturnLines

Electro-hydraulic Power Steering System

Steering Systems

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Steering Maneuver

Load

SteeringWheel

Rack &Pinion Cylinder

-

+

SteeringValve

Feed Line

ReturnLine

Pump

E-Motor

M

Vehicle Speed

SteeringRate

ECU

Control

Principle of EHPS Systems

Steering Systems

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• Vehicle Performance / Safety

– Steering Feel Tuning i.e. Vehicle and/or Driver Setting

• Energy Saving

– Reduced Fuel Consumption (1 to 3 % Reduction)– High System Efficiency– Flow on demand and according to Vehicle Speed ( speed-pro feel )– Low energy consumption, in idle less than 50 Watt– Engine independent operation (Engine Shut Off)

• Future Application Criteria

– Interaction with other Chassis/Vehicle Control and Driver Assist Systems– Migration of EPHS-technology into EHS- and SBW-Applications– MPU-Utilization beyond Steering Applications (e.g. Active and Semi active

Chassis, Braking, Power Train (Automated Clutches and Transmissions)

EHPS BenefitsSteering Systems

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• Cost & Quality

– Component Assembly (HPS ) Module Assembly (EPHS) – Final Test in Car (HPS) Pre-tested System (EPHS) – Engine Independence (vs. Belt-Drive-Pump@ HPS)– Fail-Safe Operation incl. Protection Measures– System Responsibility lies with one Supplier– Simplified Supply Chain– Lower Maintenance and Warranty Cost

• Time to Market

– Steering System Tuning Flexibility in Development Process– Similar Packaging to existing Steering– Variable Position of Motor-Pump-Unit

EPHS Benefits (cont‘d)

Steering Systems

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Electric Power Steering Systems

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EPS - Scheme

Steering Systems

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Rack Drive Column Drive Pinion Drive

Electric Power Steering Systems

Electric Motor Electric Motor

Steering Systems

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Column Drive EPS

Motor / Reduction Gear/ ECU / Bracket - Assy

Manual R&P Stg Gear

Steering Systems

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39

Rack ( Belt ) Drive EPS

RCB- Screw

RCB- Nut

Belt driveMotor & ECU

Steering Systems

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END OF THE SESSION

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20/21 Mar’09